The past days people who are concerned about the fitness of the web have been abuzz over the concept of shortening URLs via the rev=”canonical” concept. The idea behind it is that resources on the web provide a hint about their everlasting short URL by means of adding a tag like <link rev="canonical" href="http://myshort.url/xyz123" />. The concept has its own blog with plenty of information.
I’m contributing my part to this in the form of a small shortening implementation for PHP 5.3. It is available under a BSD license over on github.

While it’s good to see something being done in this area, rev=”canonical” is a notoriously bad implementation and I’m disappointed that its’ promoters are still pushing it knowing that rev is deprecated and users confusing rel and rev could easily knock their site out of the search engines.
I suggest taking a look at shortlink which is a safe, standards compliant version of the same concept.
Sam
Interesting site, but much advertisments on him. Shall read as subscription, rss.
The planets are definitely starting to align for rel=shortlink, with WordPress.com adding 100 million+ pages last week and sites like PHP.net and Ars getting on board.